Twenty-three species of Ulota from South and Central America have previously been reported. A revision of the species suggests that number should be reduced to thirteen (Ulota billbuckii, Ulota fuegiana, Ulota germana, Ulota larrainii, Ulota luteola, Ulota macrocalycina, Ulota macrodontia, Ulota magellanica, Ulota phyllantha, Ulota pusilla, Ulota pycnophylla, Ulota rhytiore and Ulota streptodon) with eight names (Ulota aurantiaca = U. pycnophylla, Ulota carinata = U.fuegiana, Ulota fernandeziana = U. fuegiana, Ulota glabella = U. fuegiana, Ulota lativentrosa = U. pusilla, Ulota lobbiana = U. germana, Ulota pygmaeothecia = U. luteola and Ulota rufula = U. germana) reduced to synonyms, as well as three varieties (U. fuegiana var. crispata = U. fuegiana, U. rufula var. fagicola = U. germana and U. rufula var. patagonica = U. fuegiana). The taxonomic status of two names (Ulota angustissima and Ulota ventricosa) remains ambiguous. The typification of five names (U. macrodontia, U. magellanica, Ulota nothofagi, Ulota persubulata and U. pygmaeothecia) is proposed here. With the first report of Ulota crispa for South America, the total number of species accepted here for this region is fourteen. Two species (i.e. U. phyllantha and U. crispa) occur in both Hemispheres, one species (i.e. U. rhytiore) is only present in the Northern Hemisphere, whereas the remaining eleven species are all restricted to the Southern Hemisphere. Among them, nine (U. billbuckii, U. fuegiana, U. larrainii, U. macrocalycina, U. macrodontia, U. magellanica, U. pusilla, U. pycnophylla and U. streptodon) are restricted to South America, and two (U. germana and U. luteola) are distributed in South America and Oceania. The peristomes and spores of seven accepted species are illustrated in SEM micrographs. A key to all accepted species as well as descriptions, illustrations, synonyms, ecological and geographic distributions, and discussions are provided.
Keywords: Moss; Orthotrichaceae; South and Central America; Taxonomy; Ulota.